Rock-drill.



G. H. GILMAN.

ROCK DRILL. APPLICATION FILED JAN.15. 1912.

Patented E60. 18, 191?.

. Inveniov:

' Qeowyefi Gziman,

UNITED STATES *rn rnn'r canton.

GEORGE H. GILMAN, OF CLAREMONT, NEVT HAIVKFSHIRE, ASSIGNOR, BY' MESNEASSIGNMENTS, T0 SULLIVAN MACHINERY COMPANY, OF BOSTON, MASSAGE-TU SETTS,A CORPORATION OF MASSACHUSETTS. V i c ROCK'-IDRILL..

Original application filed July 6, 1911, Serial No. 857,100. Divided andthis application filed January 15','

Specification of Letters Patent.

1912. Seria1No.67 1,376.

To all whomz't may concern Be it known that I, G ORGE H. GILMAN, acitizen of the United States, and a resident of Claremont, county ofSullivan, State of New Hampshire, (whose post-ofiice address isClaremont, New Hampshire) have invented an Improvement in Rock-Drills,of whichthe following description, in connection with the accompanyingdrawings, is'a specification, like characters on the drawingsrepresenting like parts. i

This invention relates to rock drills, being more particularly intendedto provide an efficient but simple construction of drilling tool.

This application is a division of my prior co-pending application SerialNo. 637,100, filed 'July 6, 1911. I

The invention will be best understood by reference to the followingdescription when taken in connection with the accompanying illustrationof one specific embodiment thereof, submitted for illustrative purposesonly, while its scope will be more particularly pointedout in theappended claims.

In the drawings: v

Figure 1 is a plan view of a portion of a rock drill embodying one formof the invention;

Fig. 2 is an elevation inpartial section of the construction shown inFig. 1; and I Fig. 3 is a section in plan of a modified form of fronthead.

Referring to the drawings and to the embodiment of the invention thereillustrated, I have shown the same embodied in a rock drill the cylinderwhereof is shown at 1, the piston at 2, the latter being connected to apiston rod 3 adapted to carry at its outer end a chuck (not shown) forreceiving the drill.

The front end of the cylinder is closed by a head of improvedconstruction through which the piston rod passes. Referring to Figs. 1and 2, the front head comprises a ring head 1, the upper end of which isfrustoconical and is counterbored to fit accurately the outside of thecylinder. The forward end of the cylinder is preferably turned on theoutside to make it concentric with the bore and to receive theoverlapping end of the ring head. Seated within the cone shaped end ofthe ring head isa split bushh1g5 which has a projection 6 of reduceddiameter entering a counterbored portion of the cylinder. The forwardend of the ring head is partially split and internally threaded, and isprovided with a gland 7 in the form of a split bushing with stud joints.The opposing ends of the gland and bushing are beveled so that they tendto compress packing S,which is clamped between them, against the pistonrod 9. The. outside diameter of the gland is slightly greater than thepiston so that the latter can be passed through the ring head. The headcan'be' packed by merely removing the gland and without unfastening theside rods of the drill. Both the bushing and the glandiare boredaccurately to fit the piston rod and, by means of the internalprojection 6 on the bushing and the external projection on "the ringhead overlapping the cylinder,jare kept in accurate alinement. Theseinternal and external'projections on the ring head which engage thecylinder act respectively as internal and external means for centeringor alining the head wit-h reference to the cylinder bore. They also serveto prevent leak age by providing an accurate'metallic'joint betweenthe head and the cylinder.

7 The leakage, furthermore, is not only, prevented by the overlappingshoulder on the ring head and the bushing, but also by a slightclearance 10 which is left between the bushing and the ring head. Anypressure fluid which leaks from the forward end of the cylinder tends tocondense in this space and to form awater seal rendering leakage stillmore unlikely. The ring head, as shown in Fig. 1, is provided with sidewings 11 which are perforated to receive the side rods 12, the latterbeing fastened in the front head by the nuts 13 and the interveningsprings 14.

In Fig. 3 I have shown a slightly modified form of the front head,wherein the walls of the ring head are tapered throughout their fulllength and a single bushing 15 is provided having a packing 16 placed ina groove in said bushing. This form of front head, however, is alsoprovided with internal and external centering projections similar tothose shown in Fig. 2.

At their rear ends the side rods pass through lugs 17 on the cylinderand thus serve to clamp the front head 4: and rear head 18 together. Ihave found that much breakage which occurs through the shock imparted tothe side rods by the piston striking the front head can be avoided byequalizing the shock upon the two rods. For this purpose I haveconnected the side rods by an equalizing device, herein consisting of anequalizing yoke bar 19 to the ends of which the side rods are bolted.The yoke bar has a curved inner face which rests against a preferablyflat seat provided in the end of the rear head between the lugs 20 sothat it can rock slightly thereon and tend to equalize the unequalstrains to which the side rods may be subjected, without in any wayimpairing their efficiency in clamping the cylinder and heads together.

WVhile I h ve herein shown and described for purposes of illustrationone form of the invention, it is to be understood that the same is'notlimited to the details of construction or the form or relativearrangement of parts or to the specific application of the invention,but that extensive deviations may be made therefrom Without departingfrom the spirit of the invention.

Claims. 7

1. A rock drill having a front head comprising a ring, and an innerbushing having a clearance between the same and the ring to provide awater seal and having an inner annularly disposed surface engageablewith the end wall of a cylinder.

2A rock drill having a front head comprising an internally grooved ring,and a flanged inner bushing having a clearance between the flangethereon and said groove and having inner annularly disposed surfacesengageable with the end of a cylinder.

3. A rock drill having a front headcomprising an internally groovedring, a flanged inner bushing having a clearance between the flangethereon and said groove, and a cylinder closing the end of saidclearance and having a metal to metal contact with both said groove andsaid flange.

4. A rock drill having a cylinder, a front head comprising an outer ringhaving a projection overlapping the outside of the cylinder, and aninner bushing having a projection entering the cylinder bore, aclearance being provided between the bushing and ring to afford a waterseal and said cylinder and front head presenting abutting faces inmetallic contact. 7

5. In a rock drill, an outer head ring having a projection overlappingthe outside of the cylinder and an internally tapered portion, an innerbushing disposed in the tapered portion of said ring and cooperatingtherewith to form an annularly disposed clearance space between thelatter and said projection, said bushing presenting a shoulderedprojection disposable in a cylinder bore, and a cylinder havingits endwall engageable with a surface on said bushing and its inner and outerperipheries respectively engaging the projection on said bushing and theprojection on said ring.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing Witnesses.

GEORGE H. GILMAN.

Witnesses CHAS. J. J ONES, SARAH B. FrrcH.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

